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import java.io.IOException;
import java.util.*;

import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapred.*;
import org.apache.hadoop.util.*;
/**
 *
 * @author hubert
 */
public class WordCount {
    	    public static class Map extends MapReduceBase implements Mapper<LongWritable, Text, Text, IntWritable> {
	      private final static IntWritable one = new IntWritable(1);
	      private Text word = new Text();
	
	      public void map(LongWritable key, Text value, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException {
	        String line = value.toString();
	        StringTokenizer tokenizer = new StringTokenizer(line);
	        while (tokenizer.hasMoreTokens()) {
	          word.set(tokenizer.nextToken());
	          output.collect(word, one);
	        }
	      }
	    }
	
	    public static class Reduce extends MapReduceBase implements Reducer<Text, IntWritable, Text, IntWritable> {
	      public void reduce(Text key, Iterator<IntWritable> values, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException {
	        int sum = 0;
	        while (values.hasNext()) {
	          sum += values.next().get();
	        }
	        output.collect(key, new IntWritable(sum));
	      }
	    }
	
	    public static void main(String[] args) throws Exception {
	      JobConf conf = new JobConf(WordCount.class);
	      conf.setJobName("wordcount");
	
	      conf.setOutputKeyClass(Text.class);
	      conf.setOutputValueClass(IntWritable.class);
	
	      conf.setMapperClass(Map.class);
	      conf.setCombinerClass(Reduce.class);
	      conf.setReducerClass(Reduce.class);
	
	      conf.setInputFormat(TextInputFormat.class);
	      conf.setOutputFormat(TextOutputFormat.class);
	
	      //conf.setInputPath(new Path(args[0]));
	      //conf.setOutputPath(new Path(args[1]));
              
              FileInputFormat.setInputPaths(conf, new Path(args[0]));
              FileOutputFormat.setOutputPath(conf, new Path(args[1]));
	
	      JobClient.runJob(conf);
	    }
}
